error_code_lookup

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations, so the description carries the behavioral burden, and it does disclose meaningful traits: data source (external JSON knowledge base), citation provenance, enumeration behavior when arguments are omitted, and the no-guessing fallback. It stops short of stating anything about the return shape, but an output schema exists.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded purpose, then argument modes, then coverage list, then the failure rule — every sentence carries distinct information with no repetition of the schema or title.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Output schema exists, so return values need not be re-explained. With the source, modes, covered tables, and the not-found behavior all documented, an agent has everything required to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 0% with two undocumented params, so the description must compensate — and it largely does, defining the interaction semantics of table and code (blank/only/both) and listing valid table values. It omits any format hints for the code string itself (case, prefixing).

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource: look up error codes in an external knowledge base (knowledge/error_codes/*.json) with per-entry source citations. It clearly distinguishes itself from lookup siblings (decode_register, decode_fault, symbol_lookup) by scoping to embedded/AT/Modbus/MQTT error codes.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly enumerates the three invocation modes keyed on argument combinations (table blank = list tables, table only = list codes in that table, table+code = definition/troubleshooting/source). It also names the covered tables and gives an explicit when-not rule: say 'not covered' rather than guessing another code.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.